This series re-introduces atomic write support. Some time ago support was added for O_ATOMIC in fio, but O_ATOMIC support never made it into the linux kernel, so fio support was dropped. However some plumbing was left behind; specifically, we can still pass command line arg --atomic=1, which sets thread option oatomic, but that is just ignored. Linux v6.11-rc added initial atomic write support through RWF_ATOMIC flag. See latest man pages for details of RWF_ATOMIC: https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/ This series uses the "atomic" command line option to set RWF_ATOMIC on a per IO. Support is added for libaio, pvsync2, and io_uring ioengines. Since RWF_ATOMIC is only relevant to those ioengines mentioned, trying to set --atomic=1 for other ioengines now errors. The verify feature can be useful to prove atomic writes. However, atomic writes only ensure a proper CRC, but not sequence number. So a new option to ignore sequence numbers is added. Compile tested only for Linux (ok?) Differences to RFC: - Drop patch to ignore verify sequence number - Add support for new option verify_sequence_number - Add atomic writes fio file example - Update documentation for atomic option Alan Adamson (1): pvsync2: Support RWF_ATOMIC John Garry (8): os-linux: Define RWF_ATOMIC os: Reintroduce atomic write support libaio: Support RWF_ATOMIC io_uring: Support RWF_ATOMIC tools/fiograph: Update for atomic support doc: Document atomic command fio: Support verify_write_sequence examples: Add example for atomic write verify HOWTO.rst | 25 +++++++++++++++++++++++++ engines/io_uring.c | 5 ++++- engines/libaio.c | 7 ++++++- engines/sync.c | 9 ++++++--- examples/atomic-verify.fio | 36 ++++++++++++++++++++++++++++++++++++ fio.1 | 21 +++++++++++++++++++++ init.c | 14 ++++++++++++++ ioengines.h | 2 ++ options.c | 13 +++++++++++++ os/os-linux.h | 5 +++++ thread_options.h | 1 + tools/fiograph/fiograph.conf | 6 +++--- verify.c | 7 ++++--- 13 files changed, 140 insertions(+), 11 deletions(-) create mode 100644 examples/atomic-verify.fio -- 2.31.1
